The Adding configuration is just for Calibre Standard fields.
Why not tick the
Mark newly added books Adding action, then follow up on
Marked books (ctrl Shift M) manually?
< general, not just you>

I never understood why a book needed to be marked UNREAD

If it ain't Read, the only other thing it could be is READING or it is
unread.
Is it simply a case that all boxes (fields) have to be filled with something?
This duck uses a lot of Tri-state logic. Yes, No, undetermined
I have custom date fields (done reading is one

). If it is blank, it ain't done.